A liquid crystal panel included in a liquid crystal display device of a liquid crystal display TV does not emit light, and thus a backlight device is required as a separate lighting device that supplies illumination light to the liquid crystal panel. A backlight device in which a plurality of LEDs (light emitting diodes) are arranged as light sources and they are connected in series has been known (for example, Patent Document 1).    [Patent Document 1] Japanese Unexamined Patent Publication No. 2007-305929